Well, one informal radio show is done and I had time to work on the simulator. It's lacking in tonal variety, to be honest, as I've got more "tune-like" stuff out of Boolean Sequencers before. Maybe It just needs a few more bitslices. There is room on the board for more electronics too. Anyway, this is what we have right now.

Oh, the audio comes from a VCO driven by the CV, so just a simple tone for demo purposes.

I thought it sounded like a cool bass line, or the start of one. If the affected VCO is a squarewave one you could use another 4040 to further divide the signal to get that cool octave effect, then mix together.

This approach to making CV is very familiar from playing with Lunettas, but it's definitely taking a specific route to do it, which is cool.

Les is the output of the logic stuff meant to be CV or is it also good for triggering things from the gate output?

droffset, the CD4020 and CD4060 are certainly fine alternatives for longer sequences, however only the CD4040 chip gives all 12 bits in sequence, which is a feature I really like. It sort of idealizes the BS and that seems appropriate. Nothing wrong with going with a 4020 or 4060 if that's what you have or want, though.

You bring up an interesting point about the stim. The board is intended to be a general purpose sequencer so that means it needs a CV and a GATE signal. The CV is the R2R output and the GATE is the OR of all of the logic terms. But to drive a Karplus Strong board, which is it's second mission in life, we need a stimulus pulse.

Fortunately I have experimented with Mathe's KS boards and discovered a really neat trick. If we simply place a 0.1uF capacitor in series with the CV output, into a 100kOhm load resistor, guess what? It makes a decent stim pulse. Maybe not with all the subtle adjustment qualities of a separately derived pulse (which BTW should be between 0.1 and 10 ms for the record), but still a fine stim for our purposes. So I need to add that to the circuit.

I also want to touch upon the notion of a "bitslice" approach. We want to get as much diversity of sound if that's a music term, lol, as we can from a limited board space. We want to provide the modular synthesizer user with as much flexibility for cost as possible. With the BS, one way of doing that is combining multiple BS units together.

Each would be a 1U or 2U or whatever they call it, unit, placed side by side or otherwise in the modular rack. Some daisy-chained connection joins the BS units together so that they can function as one. Then the modular synthesizer user can chain however many BS units as desired to accomplish the required complexity of sound. This will help with the "simplicity" of the sequence.

In fact, I think I'll code that up in ChucK for us to hear, post to ya soon, later...

I'm only talking CVs here.
What I would try to give more control and variation is to replace the 2*4 way gate input switches with 2*6 which are both across the 6 least significant bits. (I don't think you even need to bother with more bits than that, as it provides for a 64 step sequence. Adding access to higher bits if needed is a relatively easy option to add later.)
Then arrange the gates like this:-
Four (6way) bit switches into the dual inputs of two gates,
The outputs of those two gates into a third gate,
The output of that into a fourth plus another (6way) bit switch.
Take your 4 bits to the R2R from the outputs of these four gates.
As before, make the gate types for all four switchable.

I'm pretty sure that will allow virtually all logic combinations across 6bits into a 4bit R2R. Expand from there with a similar approach.

PS If I didn't have my hands tied under my arse I'd be breadboarding this as we speak. I've got Sat/Sun off so maybe I'll get a chance then. _________________What makes a space ours, is what we put there, and what we do there.

Uncle, I'm going to have to reread your description as it was not apparent at first glance. I'm happy to report that your original arrangement produced a really nice song when two of them are chained together. The song has diverse complexity and really rocks IMHO. I added a Karplus Strong in place of the VCO, and below you will find the source code and audio test.

OK Uncle, I understand where you're coming from with your latest suggestion. I'd say "add it to the list" of possible options. As you can hear from my previous post, your original idea gives plenty of musical interest to me at least when there are two of them.

Your second logic structure may provide more musical diversity per board, however, so it's worth a look. I do feel that your original design is more intuitive, more basic, more fundamental, etc. We'll have to see what pans out, but I like your first idea best so far.

You know the old joke that the older and wiser an engineer gets, the sloppier his schematics get, haha. By that measure you must be a sage indeed Andy! I get the idea, if I get a moment I'll prototype it in ChucK.

I got a very similar waveform from funnily enough from a custom Weird Sound Generator i've made for a friend yesterday.

How about that? I just took a quick look at the WSG block diagram and schematic. The circuits are completely different, so why would they generate similar waveforms? Perhaps the combination of a few oscillators running at different frequencies is analogous to the binary patterns that are grouped together into musical phrases, though only in the most vague sense. Thanks for noticing the similarity.

So for a repeating 16 bit sequence I'll need 4 consecutive outputs on the 4040 going to various logic gates wired per Unkle K's artowork?

Yes, that would be one way to get started droffset. You can basically hang any cloud of logic off the counter bits that you want. And you can skip bits, like use those four inputs on bits 0, 2, 4, and 6 to get a 128 bit sequence. What you listened to in the audio file of BSKS above was about 10 or 12 bits, i forget, so a 1024 to 4096 step sequence.

I got a very similar waveform from funnily enough from a custom Weird Sound Generator i've made for a friend yesterday.

How about that? I just took a quick look at the WSG block diagram and schematic. The circuits are completely different, so why would they generate similar waveforms? Perhaps the combination of a few oscillators running at different frequencies is analogous to the binary patterns that are grouped together into musical phrases, though only in the most vague sense. Thanks for noticing the similarity.

I got a very similar waveform from funnily enough from a custom Weird Sound Generator i've made for a friend yesterday.

Perhaps the combination of a few oscillators running at different frequencies is analogous to the binary patterns that are grouped together into musical phrases, though only in the most vague sense. Les

Technically in a vague sense, practically it can work that way and then some.

For this reason I'd be pleased if we could have a second 4040 with separate clock input, and have two or three of it's outputs at the rotary switches before the Gate inputs.

Another option without the need for an extra 4040 could be to have one or two inputs for external clocks. When buying rotary switches anyway, it may not be much more expensive to have nine or twelve way's instead of six way.

The latter may be the most practical solution, this being a design for a module, so have the user to decide what to insert besides the clocked 4040.
When having oscillations of similar frequency you can get these modulated short snippets of sound coming through, and you can totally alter the feel of the sequence with the sweep of the LFO speed, tune in triplets (quintuplets or anything) on the fly or apply PWM.

Multiple "base frequency" options (instead of a single clock devided by 2*2*2(etc.) (and those signals combined)) might be fairly easy to implement, and most useful imho.

Well, Mathe, I looked at the Futurlec site and 12 position rotary switches are only a dollar there (maybe a few dollars elsewhere), so a design change is in order. Perhaps not offering multiple gate types, and just using XOR gates or AND gates would be appropriate, not sure. I can only fit so many 12 position switches, so only so many inputs can be accommodated. What do you think?

The molex connectors that I'm using to connect the rotary switches to the board are only available in up to 12 positions, and the 12 position switch requires 13 positions (one for output). So I'm not sure what to do short of ignoring the last switch position. Any suggestions?

I looked at the Futurlec site and 12 position rotary switches are only a dollar there (maybe a few dollars elsewhere), so a design change is in order.

After I shut down the laptop yesterday, it occurred to me the board does not need to accommodate for extra inputs at all. All that the user would have to do is attach the six input options as envisioned by Uncle Krunkus, and directly attach the other six to either jacks for external signals, or to extra divisions from the onboard 4040, or even some post gate signals to be processed by the gate that is selected by the Gate Select rotary.

With the PCB's and 12-way rotaries being reasonably priced, having two BS boards would even be feasible. Panelspace and input jacks might become the bottleneck in that case. But then the craving for external inputs would have been greatly diminished, and one could "cross attach" the six extra rotary options from one board to the other and visa versa.

Inventor wrote:

Perhaps not offering multiple gate types, and just using XOR gates or AND gates would be appropriate, not sure. I can only fit so many 12 position switches, so only so many inputs can be accommodated.

I'm not sure either. But as long as there is space left on the PCB I'd leave the option of multiple gate types available for those who want to implement all gates. Then, if after trying , say an XOR and it serves my purpose,I could hardwire just that, and save me a rotary selector.
Next, when I pull out the XOR from the socket to try another type, I might decide I like it better, or want them both, and select two gates with a simple spdt switch. Or indeed have 4 gate types available.

Well, you get the picture I guess.
In short: provide space for 4 gate types, let the user decide what to implement.
I think it's ok to make provisions for 6-way rotary's hardwired directly on the PCB. As long as all 4040 and gate ouputs have a solderpad the user can decide what clock devisions or external signals to add when using a 12-way rotary instead of a 6-way. Likewise , a gate select switch could be either PCB mounted, or replaced by user options.

Well Mathe, I figured out how to use a 12 position switch when only 2 to 12 position Molex connectors are available. I'll just use a six and a seven position Molex connector on each 12 position switch. The board would then accomodate eight of these 12 position selectors. Still working on other details, keep you posted.

A flash of light bursts into your field of vision, startling you and drawing your fascination with it's techicolor splendor!

That's the brilliance with which I breathe new life into this long forgotten thread as I have suddenly created a modular synthesizer circuit board for the Boolean Sequencer in the past two days!

It all began when I read JingleJoe's post about what he called an ANY gate, also known in the FPGA industry as a LUT (or lookup-table or logic unit). I soon realized that this thingamajig was the perfect logic gate for the boolean sequencer modular synthesizer board! This enabling feature will be discussed in detail in a later post. Suffice to say that now I had a clear picture of how to make the board.

I'll be describing it in the following posts, with illustrations and all that jazz. The board contains five subcircuits: A counter with oscillator and four LUTs. IT's jam packed on the same exact size board as it's companion board, the Karplus Strong board and they go together well.

So kick back, relax, and prepare for a wild read as I explain in vivid detail how everything works!

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